Calorie & BMR Calculator
Estimate your Basal Metabolic Rate and daily calorie needs (TDEE) using the Mifflin-St Jeor equation.
BMR vs TDEE — what's the difference?
Basal Metabolic Rate (BMR) is the energy your body burns at complete rest, just to keep your organs functioning. Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor — it represents your real daily calorie needs including movement and exercise.
The Mifflin-St Jeor equation
This is the most accurate widely-used BMR formula for healthy adults, replacing the older Harris-Benedict equation:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Activity multipliers convert BMR to TDEE:
- Sedentary (×1.2), Light (×1.375), Moderate (×1.55), Active (×1.725), Very active (×1.9)
Calorie targets for weight goals
One pound of fat is approximately 3,500 calories. To lose ~0.5 kg (1 lb) per week, eat 500 calories below your TDEE per day. To gain weight, do the opposite. Sustainable rate is 0.5–1% of body weight per week.
Frequently Asked Questions
Should I really eat below my BMR to lose weight?
No. Eat below your TDEE (which includes activity) but at or above your BMR. Sustained eating below BMR can slow metabolism, lose muscle and harm health. A 500–750 kcal deficit from TDEE is a sustainable starting point.
Is the Mifflin-St Jeor equation accurate for everyone?
It's accurate within ~10% for most healthy adults. It can be less accurate for very lean athletes (often underestimates) and very obese individuals (often overestimates). For precise measurement, indirect calorimetry in a clinical setting is the gold standard.
How should I split macronutrients?
A common starting split is 30% protein / 45% carbs / 25% fat, but this depends on your goals (cutting, bulking, athletic performance) and personal preference. The most important macro is usually protein — aim for 1.6–2.2 g per kg of body weight to preserve muscle.